I had a root canal in a front tooth 4 weeks ago due to an abscess. After the tooth had been permanently filled by the dentist I had no problems in that tooth for a month but for the past few days it has been throbbing a bit. It's not constant and it seems to get worse with physical activites, like if I run up the stairs the throbbing will worsen. Does this mean that the root canal has failed and the abscess has returned? If this is the problem then what options might I have now? I'm quite concerned about it being a front tooth, I really don't want to have to lose it.